A 4G cellular communication system which is currently discussed is designed on the basis of one basic frame, and is also designed to optimize throughput by targeting a user who moves at low speed. Although this 4G cellular communication system is designed to support even a user who moves at high speed of 350 km/h, throughput of such high speed is less than that of low speed.
If the cellular communication system is applied to a high-speed train, link quality between a network and the high-speed train is deteriorated due to high mobility of the high-speed train of which speed is 350 km/h, and it is difficult to obtain sufficient link capacity.
In this respect, if the speed of the high-speed train exceeds 500 km/h in accordance with the development of technology, it is expected that throughput degradation may be more serious and quality of wireless data service for passengers will be deteriorated significantly. Also, the high-speed train may partially use capacity of a macro base station. In this case, it may deteriorate data communication of other users within a cell.
Meanwhile, wire communication not wireless communication may be used for communication between the network and the high-speed train. For example, although communication between the high-speed train and the network is performed through an alternating current signal by using tracks in contact with the high-speed train, such a system has problems in that capacity of the tracks is low and it is difficult to obtain more links due to physical restriction that the number of tracks for simultaneous access is limited to 2.
Likewise, although there may be provided a power line communication (PLC) system that performs communication using a power line, this system has the same problems as those of the system based on the tracks and also has a problem in that it cannot be applied to a train having no power line.
As described above, problems occur in that link capacity and quality cannot be ensured for a high-speed vehicle which moves at high speed, by the existing frame structure, the existing antenna arrangement, and the existing communication system. However, solutions for the problems have not been studied or suggested until now.